There are many different kinds of water sport devices designed to be towed behind a powered watercraft, such as a power boat. The most popular of devices have been strictly for use on the surface of the water. These devices include water skis, kneeboards and wakeboards and have been widely successful. Their success suggests potential for a devise that can travel above and below the surface while being controlled by the rider.
Another category of water sport devices are designed to be submersible, and several types of submergible devices have been proposed—for example, U.S. Pat. Nos. 6,612,254 (2002) to Arthur, 6,561,116 (2001) to Linjawi, 6145462 (1999) to Aquino, 5,605,111 (1995) to Culpepper, 5,178,090 (1991) to Carter and 5,134,955 (1991) to Manfield all describe a variety of devices that are capable of being submerged.
The device described in U.S. Pat. No. 6,612,254 is a towable underwater “kite” that has independently operated symmetrical wings positioned near the leading and trailing edges of the main body. The main body of the kite is defined by parallel support members (e.g., plastic tubes) that are interconnected with transverse struts on their ends. This defines a belly board on which the user lies in a prone position, horizontal in operation. The user operates the forward wings with his or her hands, and the rear wings with his or her feet.
The device described in U.S. Pat. No. 6,561,116 is a towable sub-aqua device that has two independently operated maneuvering planes positioned on opposite lateral sides. The main body of the device is defined by support member comprises a U-shaped bar. Each maneuvering plane has a protruding bar that is pivotally attached to the main U-shaped bar. Each protruding bar is bent 90 degrees at the inboard end making a handle.
The device described in U.S. Pat. No. 6,145,462 is a towable diver aid that has a support platform pivotally mounted within a rigid linking tubular frame. The diver is positioned on the support platform in the prone position and controls the depth by rotating the platform relative to the tubular frame.
The device described in U.S. Pat. No. 5,178,090 is an underwater diving plane that has a triangular aluminum frame. The device has a detachable transverse axle which is pivotally connected to the main frame, having two ends and two planes fixedly attached to the axle giving the diver depth control.
While the foregoing devices represent improvements in the field of technology, they also have certain disadvantages. For example, the devices described above produce lift in the downward direction when the rider directs the hydrofoils down. Buoyancy is critical for the craft to perform optimally. The majority of the prior art uses a metal tubular frame which does not provide this required buoyancy. This is a major disadvantage in that, the craft will not rise to the surface on it's own in the event that the rider comes off or becomes incapacitated.
Further, the majority of the known prior art devices use a metal or plastic tubular frame. This limits the craft to a very basic design. It does not allow the craft to be contoured around the rider's body. This is required to support the rider in the prone position. In addition, it is required to deflect the oncoming water around the rider and provide a hydrodynamic shape. Directing the oncoming water around the rider reduces the drag felt by the rider. This allows for higher speeds and more maneuverability. The lack of proper contouring by the prior art also makes the rider vulnerable to the oncoming obstacles and debris.
There is an ongoing need and opportunity therefore for improved submersible watercraft designed to be towed behind another craft.
Accordingly, several objects and advantages of my invention are:
(a) to provide a craft that is constructed of modern composite materials consisting of a sufficiently buoyant foam core and fiber reinforced polymer exterior allowing for sufficient buoyancy to counter the downward lift and provide depth control.
(b) to provide a craft that is constructed of modern composite materials consisting of a sufficiently buoyant foam core and a fiber reinforced polymer exterior allowing the craft to automatically come to the surface in the event that the rider comes off or becomes incapacitated.
(c) to provide a craft that is constructed of modern composite materials consisting of a foam core and a sufficiently ridged fiber reinforced polymer exterior allowing for complex contours that house the rider in the prone position.
(d) to provide a craft that is constructed of modern composite materials consisting of a foam core and a sufficiently ridged fiber reinforced polymer exterior allowing for complex contours that deflect the oncoming water around the rider while providing low drag, increased speeds and better maneuverability.
(e) to provide a craft that is constructed of modern composite materials consisting of a foam core and a sufficiently ridged fiber reinforced polymer exterior allowing for complex contours that wrap around the rider's hands, forearms, upper torso and shoulders to provide protection to the rider from oncoming obstacles and debris.
Other objects and advantages are to provide a craft that has two independently actuated hydrofoils where each hydrofoil is symmetric about its cord so that in its natural position, or when there is no control input from the rider, it produces no lift whereby allowing for the built in buoyancy to raise the craft to the surface. It is essential to the rider's safety that the craft raise to the surface without any control input. Further objects and advantages are to provide rapid ascent capabilities controlled by the rider. This is accomplished by placing the hydrofoils ahead of the point of pitch rotation on the craft, or the point where the tow line attaches, allowing the entire craft to pitch up when the hydrofoils are deflected up causing an increased ascent and further increasing the safety. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
In accordance with the present invention a towable under water craft comprising a main body contoured to a rider's upper torso, two independently actuated hydrofoils for controlling depth and roll and a tow line for attaching the craft to a powered water craft.